Irrigation method, irrigation apparatus, irrigation water reforming method, and irrigation water reforming apparatus

摘要

Disclosed is a method for producing a liquid fertilizer which is intended to be used in arid areas, has a water-retaining ability, and does not cause soil pollution by nitrogen contained therein. Also disclosed is a fertilization method. Further disclosed is a method for modifying an irrigation water, which can impart a satisfactory level of water-retaining ability to the irrigation water. A raw material comprising a material to be fermented and an irrigation water is subjected to methane fermentation treatment. For the purpose of reducing the nitrogen content in the resulting methane fermentation solution, an ammonia removal step is provided, in which ammonia is removed from the methane fermentation solution. Additionally, a fermentation solution modification treatment step is also provided, in which a water-retaining property is imparted to the fermentation solution from which ammonia has been removed. Thus, it becomes possible to produce a fertilizer which can reduce the soil pollution by nitrogen and has a water-retaining ability, and also becomes possible to achieve the modification of an irrigation water.